1. Field of the Invention
The present invention relates to a stator core and a spindle motor including the same, and more particularly, to a stator core having a coil wound therearound and a spindle motor including the same.
2. Description of the Related Art
Generally, a small sized spindle motor used in a hard disk drive (HDD) may be configured of a rotor and a stator.
Meanwhile, the rotor, a rotating member rotating while being supported by the stator, may include a rotor hub having a magnet installed thereon.
In addition, the stator, a fixed member rotatably supporting the rotor, may include a stator core disposed to face the magnet.
Further, the stator core included in the stator includes a coil wound therearound, the coil having power supplied thereto from the outside.
Further, the rotor hub may rotate through electromagnetic interaction between the magnet and the stator core around which the coil is wound. That is, when power is supplied to the coil, the rotor hub rotates through electromagnetic interaction between the stator core and the magnet.
In addition, as shown in FIG. 1, the stator core 10 may include a ring shaped coreback 12, tooth parts 14 extended from the coreback 12, and extension parts 16 formed at distal end portions of the tooth parts 14 and extended in a radial direction so as to increase an area facing the magnet 20.
Meanwhile, the extension parts 16 of the stator core 10 are disposed to be spaced apart from each other by predetermined intervals, such that opened areas “a” are formed between the extension parts 16.
However, when the magnet 20 installed on the rotor hub rotates together therewith, a magnitude of magnetic flux distribution changes due to the extension parts 16 and the opened areas “a” formed between the extension parts 16, and cogging torque is generated by a change in an amount of magnetic flux.
Therefore, vibrations and noise are generated at the time of rotation of the rotor hub.
Meanwhile, in order to reduce cogging torque causing these vibrations and noise, a technique of forming grooves 16a in front edges of the extension parts 16 as shown in FIG. 2 has been developed. However, in this case, gaps “g” between the front edges of the extension parts 16 and an inner surface of the magnet 20 are not constant, such that an irregular airflow occurs at the time of the rotation of the rotor hub.
Therefore, noise such as a whistling sound, or the like, may be additionally generated.